How are the three isotopes of hydrogen different from each other?

Hydrogen 1 also known as protium is typical run of the mill hydrogen - it has 1 proton and one electron. Deuterium or hydrogen 2 has a proton, neutron, and one electron. With 1 proton and 1 electron it IS hydrogen, but the atom is twice as mive as H 1. Tritium is hydrogen 3, is more mive still, and has 2 neutrons, 1 proton and one electron. Tritium is radioactive and is used in "glow in the dark" timepieces and military compes. The chemical difference is the increased m and the relative populations. Deuterium, D, is rare, tritium is scarce and their amounts in normal hydrogen are not high. There are reactivity differences. D reacts more slowly than H even in pure form because the atoms are twice as heavy and harder to move around.